20 PRACTICAL NOTES ON GRASSES AND GRASS GROWING. 
A near relation to Yorkshire fog is Hassock Grass (AIRA 
CCESPITOSA), which is a giant species of Holcus; but as it 
thrives only on wet soil, more particularly on peat tracks and 
bogs, it is not of much moment under our present heading. 
Suffice it for us to say, the seed may frequently be detected in 
’ “wood meadow grass” by its irregular shape, thick ends, and 
shiny appearance, not forgetting the white hairy fringe at the 
base of the seed. 
Dock (RUMEX OBTUSIFOLIUS). 
In docks we find several varieties, the most conspicuous 
amongst them being the common smooth-leafed field dock and 
the crimpled hard marsh dock. We have heard it remarked 
that docks die of old age, but if the originator of that remark 
ever visits our Norfolk Broads, and takes note of and examines 
the venerable dock stools which everywhere abound, he will 
have no faith in the theory he has propounded. 
Immediate action should be taken whenever docks put in an 
appearance, and every root should be extracted from the land. 
If docks are allowed to stand they soon spread themselves in 
all directions, the seed mingling with the hay and corn, and 
sheep eating the seeds (which they cannot digest) assist in 
spreading the nuisance. One autumn some years ago chance 
led us to a field in the parish of Whinburgh, in Norfolk, where 
we noticed some dock roots in a wheat stubble, and our 
attention was drawn to an insect which had eaten out the 
middle of the dock roots. This insect was unknown to us, 
and we carelessly omitted further search. 
SORRELL (RUMEN ACETOSELLA). 
Sorrell is by no means a desirable adjunct to permanent 
pastures ; its name implies its sour and unpalatable taste, and 
